Spy Fox: Spy Fox is suave, sophisticated, ever-cool and on top of things, even when the going gets a little tough. He relies on his wits and various spy gadgets, supplied to him by Quack, found at the Mobile Command Center. His mission is to save the world's cows and all their milk!
Howard Hugh Heifer Udderly III: The bovine president and CEO of Amalgamated Moo Juice Incorporated has been cownapped! Mr. Udderly is the only one who knows the extent of William the Kid's deranged plan so it's essential that Spy Fox rescue him as soon as possible. He swallows the disarming code to the Milky Weapon of Destruction. His name is based on those of Howard Hughes and Hugh Hefner, and the word "heifer."
Monkey Penny: Spy Fox's simian partner who is stationed at the Spy Corps Mobile Command Center. She sometimes contacts Spy Fox via his Spy Watch. She can also be called using the Spy Watch.
Professor Quack: is a duck at the Mobile Command Center working on spy gadgets. He'll explain to Spy Fox how each gadget works when the player clicks on them in the Spy Gadget vending machine. He has a habit of eating the gadget's blueprints after explaining the gadget's functions to the player.
William the Kid: The villain of the game, he is the CEO of the Nectar of the Goats (N.O.G.) Corporation, and plans on ridding the world of cow's milk and replacing it with goat's milk using his Milky Weapon of Destruction.
Russian Blue: A very bad kitty. She's William the Kid's right hand gal. Her life's passion is the tango – she can't resist one. She owns and operates the swank ocean liner, the SS Deadweight, where William the Kid is has been rumored to socialize. In the Car Chase Path, Spy Fox has to place a sheet of tango music within Mr. Waltz's sheet music to distract Russian Blue with a dance so Spy Fox can slip Walter Wireless into her purse to track her.
Gilbert: The vendor of the trinket stand who mainly sells trinkets, of which he claims that there are 1001 industrial uses for. There are also other things in his shop which he can't reach. The only other thing he will sell other than trinkets is a sailor's hat (needed in the White Water Path). He also has pennants with a price of 7,000,000 drachmas! He has an invitation to the SS Deadweight's Deck Party which Spy Fox will need.
Captain Drydock (seen only in the White Water path): The Captain of the SS Winaprize (the SS Deadweight's sister ship) is afraid of the ocean and highly superstitious. He lost his lucky charm at the Go Fish Table, in the cantina, and won't sail without it. If Spy Fox can win back the lucky charm, Captain Drydock will bring him wherever he wants on the sea.
Johnny Gecko: The entertainer in the cantina. All he plays is the tango because it's the only music sheet he has. During the Car Chase Path, Spy Fox must give him a sheet of waltz music in exchange for the tango music.
Mr. Waltz: He is the band conductor at the SS Deadweight's Deck Party. He plays waltz music. In the Car Chase Path, Spy Fox has to place a sheet of tango music within his sheet music to distract Russian Blue with a dance so Spy Fox can slip Walter Wireless into her purse to track her.
Sal the Sailor (seen only in the White Water Path): He's on watch duty on the bridge of the SS Deadweight. His job consists of pressing a single button, over and over, staring into space through his protruding reptilian eyes, and counting the minutes until his shift is over.
Weasel Doorman: The door man at the SS Deadweight's Deck Party who only lets people in if they have a signed invitation from Russian Blue. He is proud of his job and takes it very seriously.
Radio Room Rabbit (seen only in the Diode sidequest): He's a N.O.G. henchman in the Radio Room guarding the ten diodes. Spy Fox must distract him to get one of the diodes.
Artimice J. Bigpig: This fez wearing pig likes to play Go Fish for trinkets. Spy Fox needs to beat him in order to win back Captain Drydock's Lucky Charm in the White Water Path. If not playing for the Lucky Charm, the player can play Go Fish with him as one of the game's minigames.
Hong Kong Doodle (seen only in the Cock a Doodle Fu miniquest): This big chicken is adept at a new form of the martial art of Cock a Doodle Fu. If only Spy Fox could find the countermoves he could put this guy down for the count.
Walter Wireless the Tracking Bug (seen only in the Car Chase Path): Spy Corp's elite tracking bug whom Spy Fox uses to track Russian Blue on her speeding car by slipping him into her purse when she is distracted by a tango dance. Walter later appears near the end of the bonus ending, regardless of any path, as a news reporter. He also appears in Spy Fox 2: "Some Assembly Required".
Mata Hairy: Spy Fox's informant who appears at the Feta Factory (in a pipe) if the Car Chase Path is being played or underwater (in a treasure chest) if the White Water Path is being played. She passes Spy Fox vital information or a secret password machine.
Stewardess: The stewardess on Spy Corp's jet plane who passes Spy Fox a video from Monkey Penny hidden in a TV dinner.
Guards at William the Kid's office (seen only in the Key and Punchcard sidequests): Three guards who guard the entrance to William the Kid's office. Spy Fox has to get past them.
Tuna Boat guards (seen only in the White Water Path): Their mission is to protect the underwater entrance to Kid's Secret Base.
President Bull Clinton: The U.S. President who awards Spy Fox with the Congressinal Cookie of Justice for his efforts in defeating William the Kid and landing him in Spy Jail.